1,721,016 research outputs found
Evoked potentials with personal computer
No full textOne of the most frequently used examination in neurological diagnosis is constituted by the evoked potential (EP). In this comunication we present our project of a computerized apparatus for the acquisition and processing of EP. Firstly devoped for the analysis and processing of EP in response to visual stimuli (VEP, Visual Evoked Potentials), now is also ready for Somatosensory (SEP) and acoustical (AEP) stimuli
MIGRAINE AND EPILEPSY: LOOKING FOR A COMMON PATHOPHYSIOLOGICAL MODEL
No full textThis contribution reports about the results gathered from in-silico experiments testing the feasibility of a research
program based upon a common pathophysiological mechanism for migraine and epilepsy. In a rst set of experiments,
the Electroencephalographic (EEG) signals from couples of corresponding electrodes in the two cerebral emispheres,
as well as from couples of continguous electrodes in the left and right emisphere, were systematically correlated. In
both cases, the existence of ordered distributions of activity patterns in the EEG signals from migranious and epileptic
subjects was qualitatively assessed. In a subsequent and crucial set of experiments, we were able to obtain some
spatially ordered and oscillating synchronization patterns of virtual neurons distributed over a bidimensional region,
by means of a multi-agent simulation environment (Netlogo). On the basis of such results, a further development
of our research program including the enrichment of the data set and the consideration of other powerful simulation
approaches, e.g. Articial Neural Network (ANN) or Genetic Algorithms (GA), seems in the good track of realizing
a realistic simulation of the Cortical Spreading Depression Waves, potentially useful even for clinical purposes
EEG SIGNALS IN EPILEPSY AND MIGRAINE: Analysis and Simulations by Multi-Agent Systems
No full textThe preliminary results of some observations carried out on the spectral content of EEG signals from migran-ious and epileptic individuals and, in particular, on the spatio-temporal correlation of the neuronal activation in the two pathologies, are presented. In the aim to simulate the qualitative features of EEG signals associated to migraine and epilepsy, we used a computational approach based upon Pearson correlations and a Multi Agent System. Our findings, although still not conclusive, revealed considerable heuristic power on the sole assumption of a similar synchronization process of the underlying neuronal population, and may provide in the long term useful hints to a very difficult problem
Presentation of visual patterns of black and white striped lines of different spatial frequency in migraine patients
No full textMotor cortical inhibition and the dopaminergic system. Pharmacological changes in the silent period after transcranial brain stimulation in normal subjects, patients with Parkinson's disease and drug-induced parkinsonism.
No full textDifference in sensorimotor adaptation to horizontal and vertical mirror distortions during ballistic arm movements
No full textWhen learning a novel motor task, the sensorimotor system must develop new strategies to efficiently control the limb(s) involved, and this adaptation appears to be developed through the construction of a behavioral map known as an 'internal model'. A common method to uncover the mechanisms of adaptation and reorganization processes is to expose the system to new environmental conditions, typically by introducing visual or mechanical distortions. The present study investigated the adaptation mechanisms of the human sensorimotor system to horizontal and vertical mirror distortions (HMD and VMD) during the execution of fast goal-directed arm movements. Mirror distortions (MDs) were created by means of virtual visual feedback on a computer screen while the movement was executed on a graphics tablet. Twenty healthy adult participants were recruited and assigned to one of two groups of 10 people each. Tests were divided in two subsequent blocks of five trials. The first block consisted of trials with no mirror distortion (NMD), while the second block was recorded when exposing one group to HMD and the other to VMD. Both MDs resulted in kinematic changes: during the tests with the MDs the participants did not reach the performance level found at the NMD test. Motor performance during HMD appeared to be globally better than during VMD and the adaptation process to VMD appeared to be slower than to HMD, but data interpretation was hampered by large within-participant and between-participant variability. In-depth analyses of the data revealed that most of the motor performance information was contained in the direction of movement. The data supported the idea that the internal model for HMD was already partially built.When learning a novel motor task, the sensorimotor system must develop new strategies to efficiently control the limb(s) involved, and this adaptation appears to be developed through the construction of a behavioral map known as an 'internal model'. A common method to uncover the mechanisms of adaptation and reorganization processes is to expose the system to new environmental conditions, typically by introducing visual or mechanical distortions. The present study investigated the adaptation mechanisms of the human sensorimotor system to horizontal and vertical mirror distortions (HMD and VMD) during the execution of fast goal-directed arm movements. Mirror distortions (MDs) were created by means of virtual visual feedback on a computer screen while the movement was executed on a graphics tablet. Twenty healthy adult participants were recruited and assigned to one of two groups of 10 people each. Tests were divided in two subsequent blocks of five trials. The first block consisted of trials with no mirror distortion (NMD), while the second block was recorded when exposing one group to HMD and the other to VMD. Both MDs resulted in kinematic changes: during the tests with the MDs the participants did not reach the performance level found at the NMD test. Motor performance during HMD appeared to be globally better than during VMD and the adaptation process to VMD appeared to be slower than to HMD, but data interpretation was hampered by large within-participant and between-participant variability. In-depth analyses of the data revealed that most of the motor performance information was contained in the direction of movement. The data supported the idea that the internal model for HMD was already partially built. (c) 2005 Elsevier B.V. All rights reserved
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